"For years, PC programmers used x86 assembly to write performance-critical code. However, 32-bit PCs are being replaced with 64-bit ones, and the underlying assembly code has changed. This white paper is an introduction to x64 assembly. No prior knowledge of x86 code is needed, although it makes the transition easier."

I wonder if I even kept my Vax assembler lang ref, that was almost a high level language architecture right there, codes that could be up to 20 bytes long or so. Pascal and other structured statements almost right in the instruction set and the antithesis of the coming RISC chips from Stanford (MIPS) and Berkeley (SPARC) and others.

My true love was the 68000 and later, so easy to do 32b code without any fuss or muss, even self modifying types of code till protection came along.

I never got into x86 until I got the books like "Inner Loops" by Booth and some others. That finally made a case to look it over and learn a bit about Pentium pipeline pairing, but by then the Athlons and newer Intel chips made any optimization attempts moot. No predictability at all, very un risc to me.

Plain C code now runs as fast as any assembler because the op odes are free, the memory references are free as long as they are in cache. Assembler is likely only worth doing for DSP codecs.